In [1]}, different choices were made for the parameters in the
convolution product ansatz () for \(h_{\mu \nu }\) . Specifically,
in [1]} the structures involving \({\partial }j\)  or \({\partial }\tilde{j}\)  in
\(j_{\mu \nu }(h)\)  given in eqn (REF ) were required to be absent,
together with requiring \(a_4=0\) . After imposing also the conditions
for BRST and anti-BRST invariance, this leads to the conditions given in
eqns (18a), (18b) and (18c) in [1]}, namely
\(a_1 &=& {\frac{1}{1-\xi }} \,,\qquad a_2={\frac{1+\xi }{2(1-\xi )}}\,,\qquad a_3=-{\textstyle {\frac{\scriptstyle 1}{\scriptstyle 2} } }\,,\qquad a_4= 0\,,\nonumber \\b_1 &=& -{\frac{\xi }{(2-D)(1-\xi )}}\,,\qquad b_2= -{\frac{1}{(2-D)(1-\xi )}}\,,\qquad b_3= -{\frac{(1+\xi )}{(2-D)\,\xi }}\,.\) 
